In a bar in St Germain, Paris, Luis Buñuel, one of the world's great film-makers, is taking his son for an aperitif. This, Buñuel tells the boy, is one of the places where he used to come with his friend Salvador Dali when he was a young surrealist in the Paris of the late 1920s. They order their drinks and settle back to enjoy them. Suddenly, a Rolls-Royce pulls up at the door. Out of it clambers Dali and his entourage. They sweep through to a private room upstairs. Buñuel and son bury their faces in their menus. They are desperate not to be spotted.
Juan Luis Buñuel tells this story to show just how frayed the relationship between his father and Dali had become. In the early 1920s, Buñuel, Dali and a third, equally distinguished figure, the writer Federico Garcia Lorca, were as close as brothers. They had met as students at the Residencia De Estudiantes in Madrid and had run wild together. They were very different personalities. Buñuel was a self-styled "brute from Aragon". Lorca and Dali were more refined. Nevertheless, the three students relished one another's company. Once, toward the end of his life, Buñuel took his son to Toledo, where he, Lorca and Dali used to get up to mischief during their student days. "We went for a nice supper and then, at midnight, we tried to get lost on the streets - which is what he used to do with Dali and Lorca. Finally, we ended way up on this balcony, gazing at the city below. He was all teary. I asked what was the matter. He said that this was where he used to come with Federico and Salvador. We would come here to vomit."
By the time Buñuel and Dali almost came face to face again in the Paris bar, Lorca was long dead (he was killed during the Spanish Civil War) and the other two men were no longer on speaking terms. There was no nostalgic reunion. "My father said that, if he was to see Dali now, he would fall into his arms, but he knew that, within 20 minutes, there would be 60 reporters there, brought in by Dali."
Whether his wife Gala was to blame, or whether he was fonder of fame and money than old friends (André Breton pointed out that his name was an anagram for "avida dollars" - suggesting a greed for money), Dali had betrayed Buñuel. "What a man!" Juan Luis says, "I mean that in a bad sense. He blew it all! He was a bad friend... He was not a stupid man but, for 50 years, he dropped all of his friends, and went out with cretins."
Juan Luis cites a letter the artist wrote to his father when Buñuel and his family were eking out an existence in New York in the late 1930s. "We didn't have any money," Juan Luis recalls. "We were living in a kitchenette apartment. My father asked Dali, 'please can you lend me $50. I am starting work at the Museum Of Modern Art and I'll pay you in a month'. Dali's answer was: 'No, you don't lend money to friends - and thank goodness that Franco won the war."
As if that wasn't bad enough, Dali subsequently got Buñuel fired from the Museum of Modern Art by describing him as "an atheist." After that, Buñuel wouldn't go near Dali. "Until the very end of their lives, Buñuel refused to have anything to do with Dali," says Buñuel's close friend, and screenwriter, Jean-Claude Carrière.
The brief partnership between Buñuel and Dali yielded two films, both acknowledged as surrealist classics. The first was Un Chien Andalou (1928), financed with money from Buñuel's mother and co-directed by Dali. As Buñuel recounts in his autobiography, My Last Breath, the project had its roots in a dream, in which "a long tapering cloud sliced the moon in half, like a razor blade slicing through an eye". Buñuel recounted this dream to Dali who immediately responded that he had just had a dream of his in which he had seen a hand crawling with ants. The duo set to work bouncing ideas off each other. Within a week, they had completed the script. "Our only rule was very simple. No idea or image that might lend itself to a rational explanation of any kind would be accepted. We had to open all doors to the irrational and keep only those images that surprised us, without trying to explain why," Buñuel recalled.
Un Chien Andalou was warmly received by Parisien high society but the duo's next collaboration, L'Age D'Or (1930) was given an altogether rougher reception. Fascist sympathisers attacked the theatre where it was showing and threw ink at the screen. The film wasn't shown again in Paris for close to 50 years. Thus ended the artistic collaboration between Buñuel and Dali.
As Dali became richer and richer, and more and more famous, Buñuel had a far more chequered career. After the Spanish Civil War, Buñuel headed briefly to Hollywood, but was unable to find work. He eventually ended up in Mexico, where he resumed film-making in the mid-1940s. His international re-emergence came with Los Olvidados (1950), which won a prize in Cannes.
Luis Buñuel grew up in Calanda, a small town in Aragon that, even in the early 20th century, seemed rooted in the Middle Ages. The town was isolated. There was little in the way of culture and the church was all-powerful. "Religion permated all aspects of our daily lives; I used to play at celebrating mass in the attic of our house, with my sisters as attendants," Buñuel wrote. His reaction against the "blind faith" of his childhood would drive his art. As his son puts it today: "He was a complete atheist. The very idea that God existed made him laugh." His anger at the Catholic Church was exacerbated by what had happened during the Spanish Civil War. Buñuel spent much of his subsequent career mocking and subverting Christianity.
The picture Juan Luis sketches of his father is of an austere man with a caustic sense of humour. Buñuel never talked about film-making at home. "When my brother was 15, somebody asked him if his father made films and he wasn't sure. At home, we talked about the civil war or literature. We didn't talk about films. For us, our father was a man who was sitting at his desk reading or writing."
Buñuel's Mexican movies were made with next to no money. Often, he was working on what his son calls "really stupid stories". Nonetheless, such movies as The Great Madcap (1949) or Ascent To Heaven (1952) had his unmistakable imprint. "Technically, he was fantastic. You don't feel the technique," says his son. "It's like a Picasso drawing where he just draws the face. Go ahead and try to do the same thing!"
Like any good surrealist, Buñuel fretted when his films were popular. After all, he had once described cinema as "a desperate and passionate appeal to murder". It threw him when bourgeois cinemagoers flocked to his work. "What did I do wrong?" he would ask himself when he found an audience. Nor did he have much affection for stars. He cast Catherine Deneuve in Belle De Jour simply to keep his producer happy. His son says he had no desire to work with Jeanne Moreau on Diary Of A Chambermaid (1964) either and only relented once he went to dinner with her. "She had a plateful of garlic and she was sopping it up with bread, eating the garlic and drinking red wine. He then thought she was wonderful."
Most of Buñuel's movies have a warped, dream-like feel. The middle classes, policemen and priests are invariably in the firing line. "I have a cousin who says that if you take all of my father's work, except for Robinson Crusoe (1954) and one or two others, it's the same film," Juan Luis notes.
In New York and then in Mexico, Juan Luis realised the hardships his parents were enduring. "My mother had one dress which at night she'd wash and then iron. But it didn't seem to matter. My father made enough to pay the rent." Juan Luis argues that his father would have been amazed to discover that he is still being fêted more than 20 years after his death (in 1983).
And what was the key to Luis Buñuel's creative imagination? "He would go to bed at eight... to dream."
The Buñuel season runs at the National Film Theatre until the end of February. His 'Los Olvidados' is re-released on 16 February